New Zoantharian Species Discovered Near Okinawa

Posted on July 22, 2016

Scientists have discovered a new zoantharian species. It is the first described solitary species in over 100 years. It does not live in colonies like other zoantharians. The species was discovered SCUBA surveys around the southern Japanese island of Okinawa.

The researchers Drs Takuma Fujii and James Davis Reimer, affiliated with Kagoshima University and University of the Ryukyus, found the creatures were buried almost completely in the soft sediment of the seafloor. Only their oval disks and tentacles protruded above the surface. An individual polyp removed from the sand is pictured below.

Most known zoantharians are colonial and many dwell in shallow waters of subtropical and tropical regions, where their large colonies can be found on coral reefs. These newly discovered polyps were leading solitary lives. They were also found to lack zooxanthellae, single-celled organisms that coexist in symbiosis with certain marine invertebrates. Most zoantharians have them.

Dr. James Reimer says in a statement, "The only reason this species was discovered was that the right person was in the right place at the right time. Such research also shows how important it is to have specialist researchers participate in surveys - otherwise, we might be missing a lot of the biodiversity present in the marine realm simply because we don't know what we are looking at."

The new species has been named Sphenopus exilis. It is about 3 centimeters in length. It is only known to live on two bays on the east coast of Okinawa island. Both of these bays are currently threatened by development. A research study on the new species can be found here in the journal, ZooKeys.

ANIMALS